package total;

import java.util.Scanner;

public class Ques1808 {
	
	public void go(){
		Scanner scan = new Scanner(System.in);
		int n;
		String str1,str2,str3="A";
		while(scan.hasNext()){
			n = scan.nextInt();
			str1 = "A";
			for(int i = 1;i < n;i++){
				str2 = (char)('A'+i)+"";
				str1 = str3 + str2 + str3;
				str3 = str1;
			}
			System.out.println(str3);
		}
	}
	
	public static void main(String[] args) {
		new Ques1808().go();
	}
}
